MIC809/MIC810 Microprocessor Reset Circuits MIC809/MIC810 Microprocessor Reset Circuits Description Pin Configuration The MIC809/MIC810 are inexpensive microprocessor supervisory circuits that monitor power supplies in microprocessor based systems. The function of these devices is to assert a reset if the power supply drops below a designated reset threshold level. Several different reset threshold levels are available to accomodate 3V, 3.3V or 5V powered systems. The MIC809 has an active low RESET output, while the MIC810 offers an active high RESET output. The reset output is guaranteed to remain asserted for a minimum of 140ms after VCC has risen above the designated reset threshold level. The MIC809/MIC810 come in a 3pin SOT-23 package. Typical Applications · Portable Equipment · Intelligent Instruments · Critical Microprocessor Power Monitoring · Printers/Computers · Controllers Reset Threshold Voltage (V) 4.63 4.38 4.00 3.08 2.93 2.63 Device Suffix L M J T S R Top View GND 1 MIC809 3 VCC MIC810 3 VCC RESET 2 GND 1 RESET 2 Features RESET Remains Valid with VCC as Low · as 1.4V Voltage Monitor for 3V, 3.3V · Precision or 5V Power Supplies · Available in 3-Pin SOT23 Package · <15µA Supply Current · 140ms Minimum Reset Pulse Width · No External Components Required Typical Operating Circuit Ordering Information Part MIC809_U MIC810_U Package 3-Lead SOT23 3-Lead SOT23 Temp. Range -40°C to +85°C -40°C to +85°C Place the device suffix of desired reset threshold voltage from table above in blank to complete the part number. VCC VCC VCC MIC809 µP RESET RESET 1 MIC809/MIC810 Microprocessor Reset Circuits Absolute Maximum Ratings Terminal Voltage VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 6.0V Input Current, VCC, . . . . . . . . . . . . . . . . . . . . . . . 20mA Output Current, RESET, RESET . . . . . . . . . . . . . .20mA Rate of Rise, VCC . . . . . . . . . . . . . . . . . . . . . . 100V/µs Operating Temperature Range MIC809-U, MIC810-U . . . . . . . . . . . . . . . -40°C to 85°C Storage Temperature Range . . . . . . . . . . . . .-65°C to 150°C Lead Temperature (Soldering - 10 sec.) . . . . . . . . . . . 300°C Power Dissipation (TA = +70°C) . . . . . . . . . . . . . . . . 320mW Stresses above those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent device failure. Functionality at or above these limits is not implied. Exposure to absolute maximum ratings for extended periods may affect device reliability. Operating ranges define those limits between which the functionality of the device is guaranteed. Electrical Characteristics VCC = 5V for MIC8--L/M/J, VCC = 3.3V for MIC8--S/T, VCC = 3V for MIC8--R, TA = Operating Temperature Range, unless otherwise noted. Parameter Conditions Operating Voltage Range, VCC TA = 0°C to 70°C TA = -40°C to 85°C Supply Current, ICC MIC809L/M/J, MIC810L/M/J VCC < 3.6V, MIC809R/S/T, MIC810R/S/T Reset Voltage Threshold, VTH MIC809L, MIC810L MIC809M, MIC810M MIC809J, MIC810J MIC809T, MIC810T MIC809S, MIC810S MIC809R, MIC810R Reset Timeout Period RESET Output Voltage, VOH ISource = 800µA, MIC809L/M/J ISource = 500µA, MIC809R/S/T RESET Output Voltage, VOL VCC=VTH Min., ISink=3.2mA, MIC809L/M/J VCC=VTH Min., ISink =1.2mA, MIC809R/S/T VCC>1.4V, ISink =50µA, TA = 0°C to 70°C VCC>1.6V, ISink =50µA, TA = -40°C to 85°C RESET Output Voltage, VOH 1.8V < VCC < VTH Min., ISource = 150µA RESET Output Voltage, VOL ISink=3.2mA, MIC810L/M/J ISink=1.2mA, MIC810R/S/T 2 Min Typ Max Units 5.5 5.5 V 9 6 15 10 µA 4.50 4.25 3.89 3.00 2.85 2.55 4.63 4.38 4.00 3.08 2.93 2.63 4.75 4.50 4.10 3.15 3.00 2.70 V 140 240 560 ms 1.4 1.6 VCC - 1.5V 0.8 X VCC V 0.4 0.3 0.3 0.3 0.8 X VCC V V 0.4 0.3 V MIC809/MIC810 Microprocessor Reset Circuits Pin Functions Pin No. Pin Name MIC809 MIC810 GND 1 1 RESET 2 N/A RESET goes low if VCC falls below the reset threshold and remains asserted for one reset timeout period (140ms min.) after VCC exceeds the reset threshold. RESET N/A 2 RESET goes high if VCC falls below the reset threshold and remains asserted for one reset timeout period (140ms min.) after VCC exceeds the reset threshold. 3 3 Power supply input, 3V, 3.3V or 5V. VCC IC Ground Pin. 3 MIC809/MIC810 Microprocessor Reset Circuits Block Diagram + VCC (3) Reset RESET GENERATOR - Threshold (V) GND (1) Figure 1. MIC809/810 Block Diagram 4 RESET (2) RESET (MIC810) MIC809/MIC810 Microprocessor Reset Circuits Circuit Description Microprocessor Reset The RESET pin is asserted whenever VCC falls below the reset threshold voltage. The reset pin remains asserted for a period of 240ms after VCC has risen above the reset threshold voltage. The reset function ensures the microprocessor is properly reset and powers up into a known condition after a power failure. RESET will remain valid with VCC as low as 1.4V. VCC Transients The MIC809/MIC810 are relatively immune to negativegoing VCC glitches below the reset threshold. Typically, a negative-going transient 125mV below the reset threshold with a duration of 50µs (25µs for MIC8__R/S/T) or less will not cause an unwanted reset. VCC Vthr Vthr t1 t1 RESET Figure 2. Reset Timing Diagram Interfacing to Bidirectional Reset Pins The MIC809/MIC810 can interface with µPs with bidirectional reset pins by connecting a 4.7KΩ resistor in series with the MIC809/MIC810 output and the µP reset pin. VCC VCC VCC MIC809 µP RESET RESET 100K RESET Valid to 0V A resistor can be added from the RESET pin to ground to ensure the RESET output remains low with V CC down to 0V. A 100KΩ resistor connected from RESET to ground is recommended. The size of the resistor should be large enough to not load the RESET output and small enough to pull-down any stray leakage currents. Figure 3. RESET Valid to VCC = OV 5 MIC809/MIC810 Microprocessor Reset Circuits Alternate Source Cross Reference Guide Industry P/N 6 MIC Direct Replacement MAX809JEUR-T MIC809JU MAX809LEUR-T MAX809MEUR-T MAX809REUR-T MAX809SEUR-T MAX809TEUR-T MAX810JEUR-T MIC809LU MIC809MU MIC809RU MIC809SU MIC809TU MIC810JU MAX810LEUR-T MAX810MEUR-T MIC810LU MIC810MU MAX810REUR-T MAX810SEUR-T MIC810RU MIC810SU MAX810TEUR-T MIC810TU MIC809/MIC810 Microprocessor Reset Circuits Packaging Information U Package, 3-Pin SOT-23 Small-Outline Transistor Package 0.021 0.015 0.055 0.098 0.047 0.083 0.120 0.105 0.0059 0.0035 0.040 0-8¼ 0.031 0.079 0.071 0.004 0.001 0.010 0.005 Dimensions are in inches. Device Marking Information Lot Code IJXX ILXX IMXX IRXX ISXX ITXX JJXX JLXX JMXX JRXX JSXX JTXX = = = = = = = = = = = = MIC809J MIC809L MIC809M MIC809R MIC809S MIC809T MIC810J MIC810L MIC810M MIC810R MIC810S MIC810T 7 MIC809/MIC810 Microprocessor Reset Circuits Packaging Information Tape and Reel Information 4.0±0.1 ¯1.5±0.1 1.75±0.1 2.0±0.05 3.5±0.05 8.0±0.3 4.0±0.1 2.7±0.1 1.2±0.1 3.1±0.1 Dimensions are in millimeters. 8 ¯1.1±0.1